Mechanical, Tribological, and Corrosive Properties of NbCrC_x and NbCrC_xN_y Coatings with Various Nitrogen and Carbon Contents

CrC and NbC carbide coatings both have good mechanical properties, wear resistance, and corrosion resistance. The present study seeks to combine the two coating systems in order to further enhance their properties. NbCrCx and NbCrCxNy coatings (where x and y denote the atomic percentages of carbon and nitrogen, respectively) were deposited on SKH51 substrates using a radio-frequency unbalanced magnetron sputtering system. The mechanical, tribological, and corrosive properties of the coatings were investigated and compared. Among the NbCrCx coatings, the NbCrC61 coating showed high levels of hardness, excellent adhesion strength, and good wear resistance. Among the NbCrCxNy coatings, the NbCrC55N5 coating showed high adhesion strength and hardness and excellent tribological properties. However, for nitrogen contents greater than 16 at%, the adhesion strength was dramatically reduced, resulting in poor tribological performance. Among all of the coatings, the NbCrC49 coating showed the best corrosion resistance due to its enhanced crystallinity, high adhesion strength, moderate surface roughness, and high sp3 C-C bonding ratio

Microstructure, phase transformation and hardness of nanometric Cr-Al multilayer coatings

Nanometric Cr-Al multilayer films are deposited by magnetron sputtering to investigate the influences of composition and annealing on the microstructure, phase transformation, and hardness. The enhancement of hardness of as-deposited coatings is attributed to solid solution strengthening and grain size strengthening. For the Cr100−xAlx coatings with x = 30 at.% and x = 62 at.%, respectively, the annealing process prompts the formation of Cr2Al and Cr5Al8 intermetallic compounds. The enhancement of hardness of annealed coatings is primarily caused by the intermetallic formation and secondarily by oxide layer formation